And let's not forget that every time some promising alternative appears Facebook either fast follows (i.e. plagiarizes) it, or buys it and buries it in a hole somewhere.
This. That's the problem. It's not just one company unfairly being screwed by Apple. They've lied about everything else.
Has Facebook ever done this to an alternative that wasn’t just ‘Facebook 2’, ie. it would have solved the problems and grievances people here have with the Facebook platform?
Hard to say, as many of the industry’s more famous acquisitions/destructions were before any effective attempts to monetise.